1. Field of the Invention
The present invention relates to an aligner.
2. Prior Art
In recent years, print circuit boards go on fineness with lightness, thinness, shortness, smallness, and high function of products typified by a portable telephone. Especially, in order to increase numbers of electric parts mounted on the board, a board by a manufacturing method called build-up, which is formed on whole faces called through-hole hitherto, and which has no hole is on the market. This board forms resin insulation layers and conductive patterns of copper alternately in order on top and bottom of inserted layer board called core board. Conductivity between layers is made by forming a hole called via hole and plating copper.
Here, at forming a pattern of a build-up layer formed on top and bottom of the core board, it is need to perform positioning of alignment mark on the core board and alignment mark set on a photo mask for build-up layer in order to make sure of mutual position relation of the pattern already formed on the core board and the pattern of build-up layer.
However, whole faces are covered by copper foil before pattern forming of the build-up layer, so the alignment mark on the core board is not seen usually.
Because of that, hitherto, in method forming copper foil of the build-up layer, method putting masking tape on and taking it off after plating is adopted so that plating is not attached at part corresponding to a mark on the core board. As another method, there is a method using holes for a mark of the core board without using the pattern. In the method, it is need to prevent resin from invading into the core board or to remove the resin invaded so that the hole is covered at next plating when resin insulation layer of the build-up layer is applied. In the method forming by putting copper foil, process is difficult because copper foil portion is etched once and is removed so as to be neck for efficiency of process.
In order to solve the above-mentioned problem, applicant of the invention developed technique of positioning by reading an alignment mark on a board formed on a core board using X-ray. However, at using the X-ray, there is a problem that composition of photo mask changes by the X-ray and transparency of part irradiated by the X-ray deteriorates especially in the case of glass photo mask.
An object of the invention is to aim for new improvement about the above-mentioned aligner positioning by using the X-ray.
To achieve the above-mentioned object, the invention is characterized by comprising: a photo mask enabling to arrange at one side of a board forming a multi-layered circuit and drawing conductive patterns formed on the board; a board alignment mark formed on at least one layer of the board and enabling to photograph by an X-ray; a mask alignment mark drawn on the photo mask; an X-ray generator irradiating X-ray to an area including said board alignment mark; means for removing the photo mask out of X-ray irradiation range of the X-ray generator; a projecting member enabling to convert the X-ray to visible light, ultraviolet rays, or infrared rays and to which an image of the board alignment mark irradiated using the X-ray is projected; a unit detecting position of the board alignment mark projected to the projecting member; a unit detecting position of the mask alignment mark of the photo mask at the state being arranged at one side of the board; a moving unit for moving one of the board and the photo mask or both so that positioning of the board and the photo mask is performed based on the detected board alignment mark and mask alignment mark; and an exposure light source exposing a pattern drawn on the photo mask after the positioning onto the board in the aligner for manufacturing a multi-layered printed circuit board having plural insulation layers and plural conductive layers drawing conductive patterns.
In the above-mentioned constitution, it is possible to project image of the board alignment mark formed on the core board to the projecting member using X-ray so as to perform positioning of the board and the photo mask based on the board alignment mark and the mask alignment mark.
Moreover, because the photo mask can be removed out of X-ray irradiation of the X-ray generator range, change of composition of the photo mask by the X-ray can be prevented.
The aligner further comprises means for obtaining position relation from the detected positions of the board alignment mark and mask alignment mark and detecting a gap from previously determined position relation and it is possible to perform positioning of the board and the photo mask based on the gap. For example, the board alignment mark and the mask alignment mark may be moved so as to meet. The moving is possible to move one of the board and the photo mask or both. The control of the moving unit may be performed automatically or manually.
In the preferred embodiment, the aligner further comprises means for memorizing position of the detected board alignment mark, the moving unit moves one of the board and the photo mask or both based on the memorized board alignment mark and the detected mask alignment mark. Even in this case, it is possible to detect a gap based on position relation of the memorized board alignment mark and the detected mask alignment mark.
It is possible to provide means for memorizing position of the board besides the board alignment mark, to set an imaginary board, to memorize position of the board alignment mark in relation to the memorized board, and to set the position of the board alignment mark on the imaginary board. In this case, the moving unit moves one of the board and the photo mask or both based on the board alignment mark on the imaginary board and the detected mask alignment mark. It is possible even that a gap is detected based on position relation of the board alignment mark set on the imaginary board and said detected mask alignment mark. The aligner further comprises a unit displaying the detected positions of the board alignment mark and mask alignment mark as image, one of the board and the photo mask or both may be moved so that the board alignment mark and the mask alignment mark become previously determined position relation based on the displayed image.
In the case setting the imaginary board, the imaginary board and the photo mask are displayed as image. Even in this case, it is possible that the moving unit moves one of the board and the photo mask or both so that position relation of the board alignment mark on the imaginary board and the mask alignment mark becomes designated position relation. The unit detecting the board alignment mark and the unit detecting the mask alignment mark include a CCD camera usually, and positions of the board alignment mark and the mask alignment mark are detected based on image signal photographed by the camera.
The above-mentioned constitution has advantage when the photo mask is a glass mask or a glass putting a photo mask of film base.